1. Field
The present disclosure relates generally to power control systems, and more particularly, to a power supply controller for allocating portions of a total thermal budget among components of a user device.
2. Background
User devices, e.g., Smartphones, tablets, laptops, etc., includes many components, such as a display, battery charger, RF transmitter/modem, central processing unit (CPU), graphics processing unit (GPU) and speaker that provide high performance features. Such features include, for example, quadcore, high resolution/brightness displays, LTE communications, 3D graphics. As the number of device features and corresponding components increase the overall thermal output of the device increase and the electrical current demand increases. Such increases may be sustainable for brief periods of time, e.g., 5-10 minutes. Beyond that time, however, operation of a device cannot be safely maintained.
Inadequate thermal cooling capability and current supply capability of such devices, particularly small scale devices with small form factors, such as Smartphones, may be detrimental to the operation of the device and thus, user's experience with the device. Furthermore, inadequate thermal cooling may not only effect the operation of the device, it may affect device longevity as well.
With respect to thermal cooling, conventional devices employ simple algorithms to limit thermal power (heat generation) and battery current. FIG. 1 is a diagram illustrating a conventional device 100, wherein a look-up table 102 is used to adjust component clock speed as a function of temperature. A multi-core processor 104 consumes an amount of power based on the frequency of operation of the processor (Pprocessor). During operation of the processor 104 some power is converted to heat. A delay 106 obtains a measure of such heat as a temperature. The temperature may be a junction temperature (Tj), which corresponds to the temperature of silicone dye in the chip transistors within the user device, or it may be a case or skin temperature (Tcase), which corresponds to a temperature of the surface of the user device case or housing. This temperature is fed back to a thermal mitigation element 108. Using the look-up table 102, the mitigation element 108 determines a core-processor frequency limit (Flimit) of operation for the processor 104 based on the temperature, and outputs the frequency limit to the processor.
Thus, in conventional systems, if the temperature of a particular component, e.g., processor, is too high, an operational aspect of that component may be throttled. In the case of a CPU or GPU, its frequency may be throttled. If the device is still too hot, additional components may be throttled. Such thermal power algorithms focus on local control of CPU/GPU temperature/power. These algorithms do not consider the quantified system-level power budget available and system overall performance as function of user experience. Nor do they provide global thermal power budget allocation to each of the components in a user device. For example, these algorithms are not scalable for various components, e.g., CPU, GPU, modem, RF, display, charger, memory, etc., inside the user device. They also do not take into consideration dynamic priority changes for each component depending on device usage scenarios. As such, conventional power control algorithms do not have the framework to optimize the overall ‘user experience’ based on particular users and usage scenarios. Each component of a user device has unique power requirements. As the usage of each component, and thus the power requirements, may be different under different usage scenarios, it would be beneficial to allocate a total power budget based on component priorities and device usage scenarios.